Apparatus for copper coating ferrous metal strip



May 8, 1945. 2,375,434

APPARATUS FOR COPPER COATING FERROUS METAL STRIP B. c. onss Er-ALOriginal Filed Nov 28, 1940 INVENTORS CMO/SE and WN Q BOLTON BOLTONCMo/sE, JR

Patented May 8, 1945 Arman-Us FOB COPPER COATING muons METAL s'rmrBolton 0. Moise, Rock Point, Ma; and Bolton 0. Moise, (in, Cambridge,Mass.

' Original application November 28, 1-940, SerialNo. 367,550. Dividedand this application January 8, 1943, Serial No. 471,754

4 Claims.

rous material has also been coated with copper by electrodeposition.

The methods using bimetallic ingots are expensive and variousdifliculties have been encountered, not only because of bad or spottybonding of the copper Jacket metal to the core or base metal, butbecause of difficulties in roll reducing such ingots to sheet-like form.

Methods in which the copper coating is obtained by electrodeposition arenot only diflicult to carry out, but are expensive, and in the mainunsatisfactory. The copper coating is more or less porous and bondingbetween the coating and the base metal is diflicult to obtain.

There is a large and growing demand for sheetlike ferrous materialhaving a non-porous copper coating or sheath which adheres to thebaseduring any manipulations ,to which the product may be put. i

An object of our invention is to provide an apparatus by means of whicha non-porous copper sheath or coat may be formed on sheet-like ferrousmaterial to produce a product which is relatively cheap and which may bedrawn, stamped or pressed without disrupting the bond between the coppercoat or sheath, and the base metal. I

Ferrous sheet-like, material having a copper coating which is joined tothe ferrous base by an alloy bond is superior to galvanized sheetlikematerial for many uses and a still further object of this invention isto provide an apparatus by means of which sheet-like ferrous material instrip form having a smooth copper coatwhich is permanently joined to theferrous body by an alloy bond may be readily produced at a relativelylow cost.

These, as well as other objects, which will be apparent to those skilledin this particular art, we attain by the means described in thespecification and more or less diagrammatically illustrated in thedrawing accompanying and forming part of this application.

In our apparatus ,of producing on a continuously moying strip ofsheet-like ferrous material a copper coating which is connected to suchstrip by an alloy bond, we take advantage of a fact, well known in theart, that when clean iron or steel at the proper temperature is wet withmolten copper while in a reducing atmosphere, a copper coating willalmost immediately be formed on this iron or steel and suchcoating willbe connected to the iron or steel base by a ferrous copper. alloy bond.

The roll stands are manipulated so that that portion of the striplocated therebetween and .within the furnace chamber is forceddownwardand position the same so that it clears the floor of the furnacechamber and avoids contact with the'walls of the furnace chamber inletand outlet openings.

The roll stands which are coupled together so 'as to operate insynchronism are then driven and the strip continuously propelled throughthe furnace chamber at the desired speed.

The strip as it passes through the heated reducing atmosphere and themolten copper bath acquires a continuous non-porous coating of copperwhich is connected to the ferrous base by an alloy bond. The coatedstrip, upon leaving the furnace chamber, travels through a temper,-ature reducing chamber in which a reducing atmosphere is alsomaintained. In this cooling chamber, the temperature of the coated stripis longitudinal section of an organized apparatus such as may be used incarrying out our novel method and is taken on line II of Fig. 2;

Figure 2 is a top plan view ofthe apparatus illustrated in Fig. 1, andin this view, the appa- Gina reduced insize to about one-third of thatof Fig. 1 and part of the means for driving the roll stands insynchronism is omitted; and

said chamber by a temperature reducing chamber H. The exit passage I5of'chamber I4 communicates with the entrance passage of furnace chamberI0 as shown in Fig. 1.

Temperature reducing chamber I4 is water jacketed and provided with awater inlet I6 and a water-outlet I1 so that cooling water may becirculated therethrough. The water jacket is also preferably providedwith heat radiating flns I8. A temperature reducing chamber l9, havingits inlet 20 connected with the outlet of furnace chamber I0 isinterposed between such outlet and exit roll stand I3.

Temperature reducing chamber I9 is also provided with a water jackethaving a cooling water inlet 2I and an outlet 22.- Heat radiating fins23.

are also preferably provided for chamber I9.

The floor of furnace chamber I II is preferably overlaid with a cover 24formed from one of the ferrous alloys which will withstand-thetemperatures encountered in the furnace chamber-j and which will notcontaminate the molten bath of copper 25 in contact therewith andcontained within the furnace chamber. Roof 26 of the furnace chambercarries electric heating elements 21. The terminals 26-28 of. theseheating elements extend through the roof and are adapted to be connectedto a suitable source of current supply. 1

Side wall 29 of the furnace chamber is provided with an opening which isadapted to be sealed by a door member 30. This door member is providedwith a peep-hole 3| and an opening 32 for accommodating a thermocouple.

Strip II in entering the organized apparatus, passes over a, guideroller 33 and under a guide roller 34. Guide roller 34 is located withina tray provided viiith sides and an end portion 41 which extend intotray or receptacle 44 to a position well below the surface of sealingliquid 45. This hood or cover 46 is provided with a reducing gas outlet48 and such outlet is surrounded by a constantly burning gas flame 49 sothat reducing gas as it escapesv through said outlet will be ignited andburned.

Shaft 50 which is the drive shaft of the lower roll 5| of roll stand I3extends through one side of hood 46 andthe Joint between said shaft andI hood side is formed toprevent the escape of reor receptacle 35 adaptedto contain suitable sealrounds roll stand I2 except for the shaft 38 of.

roll 39. This shaft extends through one side of cover or hood member 31,and the joint between said shaft and the cover or hood side is formed toprevent leakage of reducing gas through the joint. The sides of hood orcover 31 as well as end 40 thereof extend into tray or receptacle 35 toa position well below the surface of sealing liquid 36. Hood 31 isprovided with an inlet 4| for connection to a suitable source of supplyof reducing gas, such as hydrogen.

I The coated strip upon leaving roll stand I3, passes under a guideroller 42 and thence over a guide roller 43 on its way'to a coiler orshearing device as the case may be.

Guide roller 42 is located within a tray or receptacle-44 adapted tocontain suitable sealing liquid 45.

A hood or cover member 46 which joins the outer end of the water jacketof temperature reducing chamber I9 and covers roll stand I3, is

ducing gas therethrough,

Shaft 50 is provided with a worm wheel 52 and shaft 38 of lower roll 39of roll stand I2 is also provided with a worm wheel which in this caseis numbered 53.

Roll stands I2 and I3 are driven from a master worm 54 through wormwheels 55 and 56 which mesh with worm 54, and worms 51 and 58 which meshwith worm wheels 52 and 53.

The shafting between worm wheels 55 and worm 58 is provided with'adisconnectible clutch device 59, while the shafting between worm wheel56 and worm 51 is provided with a disconnectible clutch device 60.

The copper which in a molten state is charged into furnace chamber IIIto form the molten copper bath 25 is melted in a melting chamber 5|.

This chamber is preferably provided with electric heating elements 62and is connected to furnace chamber III by means of a suitable duct orpassage 63. This passage is surrounded by an electric heating element 64and the element 64 inturn is surrounded by a water jacket 65 throughwhich cooling liquid may be circulated when it is desired to rapidlyc001 passage 63.

Furnace chamber I0 is provided with a drain channel 66 and anappreciable portion of this channel as shown in Fig. 3 is surrounded byan necessary to make sure that the material is thor-' oughly descaledand has the proper surface finish.

Before entering the forward portion of the strip into position in the'organized apparatus, it is preferable to remove hoods 31 and 46. Thisgives access to the roll stands'and permits the strip to be passed underguide roller 34 through the pass of stand I2, through reducingtemperature cham ber I4 and through furnace chamber I0. .Prior to this,the door 30 of chamber I0 is removed to give access to the interior ofthe chamber for-the purpose of guiding the strip through reducingtemperature chamber I9, through the pass of roll stand I3 and underguide rollei- 42. It will be understood that during the placing of thestrip in position in the apparatus,'rol1 stands I2 and I3 are periodcally operated and manipulated by Prior to this time, a sufficientamount of copper will have been melted in melting chamber H ber Ill,reducing temperature chamber l and the seal adjacent roll stand llforces the air ahead of it through outlet ll, until the apparatus isfilled with reducing as at a pressure slightly above atmosphericpressure.

Complete filling of the apparatus with reducing gas will be indicated bythe burning of such as as it issues from outlet ll.

When the apparatus is completely fill d with reducing gas, the copperwhich is froze within channel or duct 83 is melted by turning on currentto heating elements It surrounding such duct or passage. Molten copperfrom melting chamber 6| then flows into furnace chamber l0. Sufllcientmolten copper is charged into chamber ID to submerge the lower part atleast of the strip bend. When the bath of molten copper has reached theproper depth, the current to heating element 64 is turned off andcooling water is circulated through water jacket 65 surrounding saidheating element. This freezes the copper within duct 63 and thus stopsthe flow from melting chamber tofurnace chamber I 0.

While furnace chamber III is being charged with molten copper, thecurrent to heating element 61 is cut oil and water is flowed throughwater Jacket Bl surrounding such heating element. This freezes thecopper within duct 08 leading from the bottom of furnace chamber l0 andthus seals said duct.

Duct 88 is merely used to drain furnace chamber it when repairs tothefurnace are to be made or when the bath is to be run out of the furnacechamber for lay overs. The molten copper when it is drained through duct66 is preferably led to a casting bed.

Peep-hole fl is used for observing the contour of the strip bend andconditions within the furnace chamber ill. The thermocouple enteredthrough opening 32 is used to ascertain the furnace temperature fromtime to time for regulating purposes during the operation of our coatingprocedure.

During operation of our method, cooling chamber It not only prevents thetemperature of furnace chamber Hi from reaching roll stand l2, and thuskeeps the rolls at a safe working temperature, but keeps the ferrousstrip at a temperature such that it will remain stiff and fairly rigiduntil it enters the molten copper bath or somewhat before it enters thebath. This we'believe is of assistance in maintaining the forced bend inthe strip within the furnace chamber.

During operation of our method, we maintain the temperature of thereducing atmosphere within the furnace chamber at a point just highenough to keep the copper bath in a molten condition and at the desiredtemperature. This we accomplish by regulating the temperature of heatingelements 21.

The temperature of the reducing atmosphere and. the speed with which theferrous metal strip is fed through the reducing atmosphere and moltencopper bath within the furnace chamber are so correlated that theferrous strip as it leaves the bath is of substantially the sametemperature as the bath.- Under some conditions it may be desirable tohave the temperature of the strip as it leaves the bath somewhat lowerthan that of the bath, slntiet is found that a copper coat properlybonde the ferrous metal strip and which is satisfactory for some uses,can be obtained when the strip is at such lower temperature.

It is our belief that the most satisfactory copper coat and the mostsatisfactory bond is obtained when the ferrous metal strip leaves themolten copper bath at the same temperature as the copper bath.

Under ordinary conditions, the speed of the strip, the temperature ofthe copper bath and the temperature of the reducing atmosphere are socorrelated as to obtain the best results.

It has been found that the ferrous metal strip as it leaves the moltenbath should preferably not be at a higher temperature than that of thebath. a

This application is a division of Serial No. 367,550, filed November 28,1940.

We claim:

1. In apparatus for copper coating sheet-like ferrous material in stripform, a furnace chamber adapted to contain a bath of molten copper,

two roll stands for propelling a ferrous metal strip through saidchamber, one of said roll stands being located at the inlet side of saidchamber and the other at the outlet side of said chamber, means forpositively driving said roll stands in synchronism from a common sourceof power and means for disconnecting either of such stands from saidsource of power for adjusting the bend in the ferrous strip within saidfurnace chamber.

2. In an organized apparatus for copper coating sheet-like ferrousmaterial in strip form, a furnace chamber, means for flowing moltencopper into said chamber to form a molten bath therein, roll stands onopposite sides of said chainber for propelling a ferrous metal stripthrough said chamber, means for positively driving said roll stands insynchronism, a cooling chamber between said furnace chamber and the rollstand on the entrance side of said chamber and through which said strippasses, and a temperature reducing chamber located between the outlet ofsaid furnace and the roll stand on the outlet side thereof and throughwhich said strip passes; the construction and arrangement being suchthat said cooling chamber prevents furnace temperature from reaching theroll stand on the inlet side of said furnace chamber.

3. In apparatus for copper coating sheet-like ferrous metal strip, thecombination which comprises a furnace chamber adaptedto receive and tohold a bath of molten copper, two roll stands for propelling a ferrousmetal strip through the said chamber, one of the said roll stands beinlocated at the inlet side of the said chamber and the other at theoutlet side of) the said chamber,

her, and means for controlling the temperature of the copper supplyingmeans for controlling flow of copper from the melting chamber into theholding-chamber.

, 4. In an organized apparatus for copper coating sheet-like ferrousmaterial in strip form, the combination which comprises a. furnacehaving a melting chamber and a holding chamber for metal melted in themelting chamber, means for flowing molten copper from the meltingchamber into tl'm holding chamber to form a molten bath of copper in theholding chamber, roll stands on opposite sides of the holding chamberfor propelling a ferrous metal strip through the said chamber, means forpositively driving the said roll stands in synchronism, a coolingchamber between the holding chamber and the roll stand on the entranceside of the said chamber and through which the strip passes, atemperature reducing chamber located between the outlet of the saidfurnace andthe roll stand on the outlet side thereof and through whichthe strip, passes, theconstruction and arrangement being such that thesaid cooling chamber prevents furnace temperature from reaching the rollstand on the .inlet side of the furnace holding chamber, the

said means for flowing molten copper from the melting chamber into theholding chamber including a restricted duct through which the copperflows, and means for controlling the temperature' of such duct in orderto control the fiow of molten copper therethrough.

BOLTON C. MOISE.

BOLTON. C. MOISE, JR.

